The big problem is that the Edinburgh festival starts that weekend - four weeks of hell for those of us who have to fight our way to the train station through ten times as many tourists as usual
. Not to mention that anyone who believes they have any sort of musical ability (they don't) descends on the place!
However, that aside, it means that every available place in the city is booked - people even rent out their houses for the duration of the festival, and make a lot of money for doing so.
Claymore's a couple of miles out from the centre, but not in the nicest of areas (one or the nearby estates has multiple CCTV cameras every few yards - not somewhere to get lost after dark).
It might be worth considering somewhere even as far out as Linlithgow. It's 20 minutes by train, then probably the same again by bus to Claymore (not sure about the bus, I've never done the journey).
If you want to stay on the edges of Edinburgh, there's a
Novotel at Edinburgh Park. It's not cheap, but would save the 20 minute train trip.
I'm sure others will suggest better places, but getting anywhere in central Edinburgh in August will be pushing it.
Good luck